The present invention relates to a method and apparatus for drawing out and subsequently rewinding a yarn end onto a textile yarn package and, more particularly, to a method and apparatus for separating a yarn end from the outer layer of a textile yarn package and subsequently rewinding the yarn end onto the textile yarn package in a selected manner in accordance with a determination that the yarn end has either been successfully or unsuccessfully drawn out from the outer layer of the yarn package.
One known yarn end preparation method includes the steps of applying suction to the outer layer of a yarn package to draw a yarn end from the outer layer, the application of suction occurring simultaneously with the rotation of the yarn package in an unwinding direction. If the drawing out operation proceeds without any difficulties, the length of yarn which has been drawn out from the yarn package along the suction applying conduit is of a sufficient length to extend past a location at which a yarn end cutting device is disposed. Typically, a sensor is disposed in the suction applying conduit for sensing the travel of a drawn out yarn end beyond a predetermined location in the suction conduit and the yarn end cutting device is actuated in response to the sensing by the sensor of a drawn out yarn end.
Following the step of cutting of a drawn out yarn end, the package is rotated in a winding direction to rewind the now-cut drawn out yarn end onto the outer layer of the yarn package.
In prior methods, if a yarn end drawing out operation fails to draw out a yarn end sufficiently for the sensor in the suction applying conduit to sense the presence of the drawn out yarn end, the yarn package may be deemed to be an unsuitably prepared yarn package. If such yarn packages are further transported along the textile machine, yarn ends, to the extent that they have been drawn out from the outer layer of the yarn package during the yarn end preparation process, may trail behind or alongside the yarn package and detrimentally snag on components of the textile machine along the transport path. This may occur even if the yarn package having an uncut, drawn out yarn end is still subjected to a rewinding step in which the yarn package is rotated in the winding direction to wind the uncut, drawn out yarn end onto the outer layer of the yarn package due to the reason that the yarn end may eventually loosen during further transport of the yarn package.
The snagging of yarn ends on components of the textile machine disadvantageously leads to the formation of more debris and other complications which burden the efficiency of the textile operation. The trailing ends extending loosely from the yarn packages may be eliminated, however, if the yarn end drawing out operation includes steps for detecting and handling yarn ends which have not been successfully drawn out. However, those prior art yarn end drawing out operations which merely rely upon sensing of a drawn out yarn end to initiate the step of rewinding the drawn out yarn end onto the yarn package are not sufficiently flexible to handle instances in which the yarn end has not been successfully drawn out. Accordingly, the need exists for a method and apparatus which detects and separately handles those yarn packages whose yarn ends have not been successfully drawn out so as to minimize the occurrence of trailing ends extending loosely from the yarn packages during subsequent handling of the yarn packages and thereby substatntially avoid detrimental snagging or catching of such loosely extending trailing ends.